نوع مقاله : مقاله پژوهشی
نویسندگان
پژوهشکده علوم هستهای، پژوهشگاه علوم و فنون هستهای، سازمان انرژی اتمی ایران، صندوق پستی: 8486-11365، تهران ـ ایران
چکیده
روش آشکارسازی ارتو تیروزین را میتوان برای آشکارسازی پرتودیدگی مواد غذایی سرشار از پروتئین بکار برد. به منظور اطلاع از اساس این روش، ایزومرهای تیروزین تشکیل شده در محلول‌های آبی‌فنیل‌آلانین پرتودهی شده با پرتو گاما در گستره وسیعی از دز تابش
(0.1-50kGy) مورد بررسی قرار گرفته است. اندازهگیری ایزومرهای تیروزین در محلول‌های آبی فنیل‌آلانین با استفاده از کروماتوگرافی مایع با کارایی بالا و آشکارسازی فلورسانس انجام گرفت. حد آشکارسازی ارتوتیروزین 0.01ppm و گستره خطی بودن پاسخ دستگاه برابر 0.01 تا ppm50 و انحراف استاندارد نسبی اندازه‌گیریها بین 13-4% بود. در محلول‌های آبی فنیل‌آلانین (mg/ml 1)، تا دز kGy 10 مقادیر ایزومرهای تیروزین تشکیل شده متناسب با افزایش سطح دز پرتودهی افزایش یافت اما پس از آن، افزایش بیشتر دز پرتودهی بر افزایش تشکیل ایزومرهای تیروزین تأثیر قابل ملاحظهای نداشت. در یک دز ثابت، مقدار ایزومرهای تیروزین تشکیل شده در ابتدا با افزایش غلظت فنیل‌آلانین افزایش مییابد اما افزایش بیشتر غلظت فنیل‌آلانین تأثیری در افزایش تشکیل ایزومرهای تیروزین ندارد. با دز کلی kGy10، استفاده از سرعت‌های دز
2.3kGy/h و 1.2kGy/h تغییر قابل ملاحظهای در مقدار ایزومرهای تیروزین تشکیل شده ایجاد نکرد. نتایج نشان داد در پرتودهی محلول‌های آبی فنیل‌آلانین، تشکیل ایزومرهای تیروزین تحت تأثیر دما، pH و اکسیژن محیط قرار میگیرد.
کلیدواژه‌ها
عنوان مقاله [English]
Formation of Tyrosine Isomers in Aqueous Phenylalanine Solutions by Gamma Irradiation
نویسندگان [English]
- F Aflaki
- M Salahinejad
- A Roozbehani
چکیده [English]
Ortho- tyrosine detection method can be used for detection of irradiated protein rich foods. Tyrosine isomers produced by gamma radiation of aqueous phenylalanine solutions at wide dose levels (0.1-50kGy) were examined to obtain basic information for o-tyrosine detection method of irradiated foods. Determination of tyrosines produced in aqueous phenylalanine solutions were carried out by high performance liquid chromatography and fluorescence detection. The detection limit of o-tyrosine was 0.01ppm and the linear range of calibration and the relative standard deviation of analysis was 50 ng and 4-13%, respectively. The amounts of the tyrosines increased with the irradiation level up to 10kGy and no further tyrosine formation was observed when the dose level was increased. At a constant dose level, the yield of tyrosines initially increased with the phenylalanine concentration, while with further increase of phenylalanine concentration no effect on increase of tyrosine yield was observed. When the dose rate was varying from 2.3kGy/h to 1.2kGy/h with a total amount of 10kGy in each case, there was no significant effect on tyrosine isomers formation was observed. Also the results showed that tyrosine yield was affected by temperature, pH and the presence of oxygen.
کلیدواژه‌ها [English]
- Aqueous Phenylalanine Solution
- O-Tyrosine
- Gamma Irradiation
- HPLC
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